const fp = require('lodash/fp')
// 数据
// horsepower 马力， dollar_value 价格，in_stock库存
const cars = [
  { name: 'Ferrari FF', horsepower: 660, dollar_value: 700000, in_stock: true },
  { name: 'Spyker C12 Zagato', horsepower: 650, dollar_value: 648000, in_stock: false },
  { name: 'Jaguar XKR-S', horsepower: 550, dollar_value: 132000, in_stock: false },
  { name: 'Audi R8', horsepower: 525, dollar_value: 114200, in_stock: false },
  { name: 'Aston Martin One-77', horsepower: 750, dollar_value: 1850000, in_stock: true },
  { name: 'Pagani Huayra', horsepower: 700, dollar_value: 1300000, in_stock: false },
]

// 练习一
const isLastInStock = fp.flowRight(fp.prop('in_stock'), fp.last)
// console.log(isLastInStock(cars))

// 练习二
const isFirstName = fp.flowRight(fp.prop('name'), fp.first)
// console.log(isFirstName(cars))

// 练习三
let _average = function (xs) {
  return fp.reduce(fp.add, 0, xs) / xs.length
} //无需改动
// let averageDollarValue = function (cars) {
//   let dollar_values = fp.map(function (car) {
//     return car.dollar_value
//   }, cars)
//   return _average(dollar_values)
// }
let averageDollarValue = fp.flowRight(_average, fp.map(fp.prop('dollar_value')))
// console.log(averageDollarValue(cars))

// 练习四
let _underscore = fp.replace(/\W+/g, '_') //无需改动
let sanitizeNames = fp.flowRight(fp.split(' '), _underscore, fp.join(' '), fp.map(fp.lowerCase), fp.split(' '))
// console.log(sanitizeNames([isFirstName(cars)]))
